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Voltage source converter (VSC) based high voltage direct current (HVdc) transmission draws more attention in recent years for the grid connection of large-scale offshore wind farms (WF). This paper proposes nine switch converter (NSC) based configuration and control strategy for the VSC-HVdc connected offshore WFs to enhance the fault ride through operation of the system. The configuration allows having both shunt and series interfaces to the onshore grid, which allows the isolation of the faulty part of the network, continuous power delivery to the healthy portion, and significant reduction of the fault current. Reduced switch count NSC is utilized at the onshore station to provide simultaneous shunt and series compensation to the electric grid. The proposed control strategy ensures full power evacuation and the dc-link voltage regulation during network disturbances. The comparative analysis between the proposed and conventional VSC-HVdc systems carried out in MATLAB/ Simulink environment revealed the former's enhanced transient performance. [ABSTRACT FROM PUBLISHER]

This paper proposes a new fault ride-through (FRT) configuration for a fixed-speed induction generator-based–wind turbine (FSIG–WT). It utilizes a nine-switch converter (NSC) to enable shunt and series compensation in response to the system dynamics and grid faults. The steady-state control strategy and transient-management scheme are developed to ensure proper performance in steady-state, dynamic operation as well as enhanced FRT capability of the FSIG–WT. In addition to that, the developed control strategy tackles the balanced and unbalanced operation of the electric grid with an enhanced positive- and negative-sequence compensation control scheme. The recently reported grid synchronization scheme, namely, the frequency-locked loop (FLL) is implemented to achieve fast phase detection and transient response. Consequently, the performance of the FLL has been compared with the multiple reference–frame–phase-locked loop (MRF–PLL) to demonstrate its superior performance for enhancing transient response. The proposed topology, FLL, and control strategies are verified through a comprehensive simulation study to demonstrate the enhancement of the transient response and FRT capability of FSIG-WT in adherence to grid-code requirements. [ABSTRACT FROM PUBLISHER]